Kenny Erleben - Academia.edu (original) (raw)
Papers by Kenny Erleben
The Insight Journal
OpenTissue is a multidisciplinary, open source programming toolkit for physics-based simulation, ... more OpenTissue is a multidisciplinary, open source programming toolkit for physics-based simulation, collision detection, scientific visualization, and medical imaging. The toolkit was initiated in 2001, is driven by academia, and is used by several universities. It implements several cutting edge simulators using cutting edge programming techniques. OpenTissue is available under Windows and Linux, and it implements almost all algorithms presented in the accompanying book, Erleben et al. Physics-Based Animation, Charles River Media, 2005. This presentation will give an overview of OpenTissue: what it can do, how it is done, and where the toolkit is going
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Proceedings of the International Conference on Computer Graphics Theory and Applications, 2010
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We present a computational efficient method for isotropic hyper elasticity based on functional an... more We present a computational efficient method for isotropic hyper elasticity based on functional analy-sis. By selecting a class of shape functions, we arrive at a computational scheme which yields very sparse tensors. This enables fast computations of the hyper elastic en-ergy potential and its derivatives. We achieve efficiency and performance through the use of shape functions that are linear in their parameters and through rotation into the eigen space of the right Cauchy-Green strain tensor. This makes near real time evaluation of hyper elasticity of complex meshes on CPU relatively easy to implement. The approach does not rely on a specific shape function or material model but offers a general framework for isotropic hyper elasticity. The method is aimed at interactive and accurate non-linear hyper elas-tic modeling for a wide range of industrial virtual design applications, which we exemplify by insertion of hearing aid domes into the ear canal. We validate the method for tetra...
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Abstract—In this paper, we present a method for animating multiphase flow of immiscible fluids us... more Abstract—In this paper, we present a method for animating multiphase flow of immiscible fluids using unstructured moving meshes. Our underlying discretization is an unstructured tetrahedral mesh, the deformable simplicial complex (DSC), that moves with the flow in a Lagrangian manner. Mesh optimization operations improve element quality and avoid element inversion. In the context of multiphase flow, we guarantee that every element is occupied by a single fluid and, consequently, the interface between fluids is represented by a set of faces in the simplicial complex. This approach ensures that the underlying discretization matches the physics and avoids the additional book-keeping required in grid-based methods where multiple fluids may occupy the same cell. Our Lagrangian approach naturally leads us to adopt a finite element approach to simulation, in contrast to the finite volume approaches adopted by a majority of fluid simulation techniques that use tetrahedral meshes. We charact...
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2019 16th Conference on Computer and Robot Vision (CRV), 2019
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ArXiv, 2021
Previous studies on computational modeling of tooth movement in orthodontic treatments are limite... more Previous studies on computational modeling of tooth movement in orthodontic treatments are limited to a single model and fail in generalizing the simulation results to other patients. To this end, we consider multiple patients and focus on tooth movement variations under the identical load and boundary conditions both for intra- and inter-patient analyses. We introduce a novel computational analysis tool based on finite element models (FEMs) addressing how to assess initial tooth displacement in the mandibular dentition across different patients for uncontrolled tipping scenarios with different load magnitudes applied to the mandibular dentition. This is done by modeling the movement of each patient's tooth as a nonlinear function of both load and tooth size. As the size of tooth can affect the resulting tooth displacement, a combination of two clinical biomarkers obtained from the tooth anatomy, i.e., crown height and root volume, is considered to make the proposed model genera...
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Multi-body simulations with contact are non-smooth systems and wrought with discontinuities which... more Multi-body simulations with contact are non-smooth systems and wrought with discontinuities which arise due to non-interpenetration and frictional constraints. Linear systems are used for applications where real-time performance is a concern, such as interactive training or video games, which gives rise to a linear complementarity problem (LCP). A common mathematical formulation [5] of the LCP for the velocity-level equations of motion is where J ∈ R m × n is the Jacobian matrix encoding the non-penetration and friction constraints, M ∈ R n × n is the generalized mass matrix, v and f ext ∈ R n are the generalized velocities and external forces of simulation bodies, respectively, λ ∈ R m are Lagrange multipliers representing the non-interpenetration normal forces and tangential frictional forces of each contact. The box constraints defined by z lo and z hi contain the lower and upper bound, respectively, of the normal and frictional impulses.
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Non UBCUnreviewedAuthor affiliation: University of CopenhagenFacult
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2019 International Conference on Robotics and Automation (ICRA), 2019
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In this project I describe the status of inverse kinematics research, with the focus firmly on the... more In this project I describe the status of inverse kinematics research, with the focus firmly on the methods that solve the core problem. An overview of the different methods are presented Three common methods used in inverse kinematics computation have been chosen as subject for closer inspection. The three methods are described in some detail. An analysis is performed where the three methods are compared, and benchmarked against each other. I conclude which of the methods are the most promising and what their respective forces, weaknesses and prospects are. All figures shown are made using the test suite, developed in this project and in [4]. Source code developed for this project includes the CCD method , improvements on the BFGS method and Jacobian inverse originally developed in [4]. 1
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Proceedings of the International Conference on Computer Graphics Theory and Applications, 2010
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We present the RPI-MATLAB-Simulator (RPIsim) as an open source tool for research and education in... more We present the RPI-MATLAB-Simulator (RPIsim) as an open source tool for research and education in multibody dynamics. RPIsim is designed and organized to be extended. Its modular design allows users to edit or add new components without worrying about extra implementation details. RPIsim has two main goals: 1. Provide an intuitive and easily extendable platform for research and education in multibody dynamics; 2. Maintain an evolving code base of useful algorithms and analysis tools for multibody dynamics problems. Although research often focuses on a specific subset of problems, work too often begins with developing software in a broader scope simply to realize a test bed for research to begin. It is our hope that RPIsim alleviates some of this burden by decreasing development time, thusly increasing efficiency in research. Further, we aim to provide a practical teaching tool. Because it is a fully working simulator, and since it offers the instant gratification of visualized conta...
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In this project I describe the status of inverse kinematics research, with the focus firmly on th... more In this project I describe the status of inverse kinematics research, with the focus firmly on the methods that solve the core problem. An overview of the different methods are presented Three common methods used in inverse kinematics computation have been chosen as subject for closer inspection. The three methods are described in some detail. An analysis is performed where the three methods are compared, and benchmarked against each other. I conclude which of the methods are the most promising and what their respective forces, weaknesses and prospects are. All figures shown are made using the test suite, developed in this project and in [4]. Source code developed for this project includes the CCD method , improvements on the BFGS method and Jacobian inverse originally developed in [4]. 1 Figure 2: Figure reaching for a moving ball, posed with bfgs. The figure have been constrained to obtain a more realistic pose. The source can be found at http://www.opentissue.org/svn/OpenTissue/b...
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This paper presents our adaption of an approach to achieving a virtual reality like experience on... more This paper presents our adaption of an approach to achieving a virtual reality like experience on a typical monitor using the Nintendo © [19] Wiimote. By using the infrared camera on the Wiimote combined with infrared light emitting diodes positioned on the user’s head, we achieve the effect that the content visible on the monitor adapts to the position of the head relative to the monitor. Thereby we achieve the same effect as when looking through a window; what is visible depends on the angle and distance from the window.
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Proceedings of the ACM on Computer Graphics and Interactive Techniques, 2021
We present a method for reconstructing the global position of motion capture where position sensi... more We present a method for reconstructing the global position of motion capture where position sensing is poor or unavailable. Capture systems, such as IMU suits, can provide excellent pose and orientation data of a capture subject, but otherwise need post processing to estimate global position. We propose a solution that trains a neural network to predict, in real-time, the height and body displacement given a short window of pose and orientation data. Our training dataset contains pre-recorded data with global positions from many different capture subjects, performing a wide variety of activities in order to broadly train a network to estimate on like and unseen activities. We compare training on two network architectures, a universal network (u-net) and a traditional convolutional neural network (CNN) - observing better error properties for the u-net in our results. We also evaluate our method for different classes of motion. We observe high quality results for motion examples with ...
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Computational Diffusion MRI, 2021
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ACM SIGGRAPH 2021 Courses, 2021
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Proceedings of the ACM SIGGRAPH / Eurographics Symposium on Computer Animation, 2017
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Proceedings of the International Conference on Computer Graphics Theory and Applications, 2010
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The Insight Journal
OpenTissue is a multidisciplinary, open source programming toolkit for physics-based simulation, ... more OpenTissue is a multidisciplinary, open source programming toolkit for physics-based simulation, collision detection, scientific visualization, and medical imaging. The toolkit was initiated in 2001, is driven by academia, and is used by several universities. It implements several cutting edge simulators using cutting edge programming techniques. OpenTissue is available under Windows and Linux, and it implements almost all algorithms presented in the accompanying book, Erleben et al. Physics-Based Animation, Charles River Media, 2005. This presentation will give an overview of OpenTissue: what it can do, how it is done, and where the toolkit is going
Bookmarks Related papers MentionsView impact
Proceedings of the International Conference on Computer Graphics Theory and Applications, 2010
Bookmarks Related papers MentionsView impact
We present a computational efficient method for isotropic hyper elasticity based on functional an... more We present a computational efficient method for isotropic hyper elasticity based on functional analy-sis. By selecting a class of shape functions, we arrive at a computational scheme which yields very sparse tensors. This enables fast computations of the hyper elastic en-ergy potential and its derivatives. We achieve efficiency and performance through the use of shape functions that are linear in their parameters and through rotation into the eigen space of the right Cauchy-Green strain tensor. This makes near real time evaluation of hyper elasticity of complex meshes on CPU relatively easy to implement. The approach does not rely on a specific shape function or material model but offers a general framework for isotropic hyper elasticity. The method is aimed at interactive and accurate non-linear hyper elas-tic modeling for a wide range of industrial virtual design applications, which we exemplify by insertion of hearing aid domes into the ear canal. We validate the method for tetra...
Bookmarks Related papers MentionsView impact
Abstract—In this paper, we present a method for animating multiphase flow of immiscible fluids us... more Abstract—In this paper, we present a method for animating multiphase flow of immiscible fluids using unstructured moving meshes. Our underlying discretization is an unstructured tetrahedral mesh, the deformable simplicial complex (DSC), that moves with the flow in a Lagrangian manner. Mesh optimization operations improve element quality and avoid element inversion. In the context of multiphase flow, we guarantee that every element is occupied by a single fluid and, consequently, the interface between fluids is represented by a set of faces in the simplicial complex. This approach ensures that the underlying discretization matches the physics and avoids the additional book-keeping required in grid-based methods where multiple fluids may occupy the same cell. Our Lagrangian approach naturally leads us to adopt a finite element approach to simulation, in contrast to the finite volume approaches adopted by a majority of fluid simulation techniques that use tetrahedral meshes. We charact...
Bookmarks Related papers MentionsView impact
2019 16th Conference on Computer and Robot Vision (CRV), 2019
Bookmarks Related papers MentionsView impact
ArXiv, 2021
Previous studies on computational modeling of tooth movement in orthodontic treatments are limite... more Previous studies on computational modeling of tooth movement in orthodontic treatments are limited to a single model and fail in generalizing the simulation results to other patients. To this end, we consider multiple patients and focus on tooth movement variations under the identical load and boundary conditions both for intra- and inter-patient analyses. We introduce a novel computational analysis tool based on finite element models (FEMs) addressing how to assess initial tooth displacement in the mandibular dentition across different patients for uncontrolled tipping scenarios with different load magnitudes applied to the mandibular dentition. This is done by modeling the movement of each patient's tooth as a nonlinear function of both load and tooth size. As the size of tooth can affect the resulting tooth displacement, a combination of two clinical biomarkers obtained from the tooth anatomy, i.e., crown height and root volume, is considered to make the proposed model genera...
Bookmarks Related papers MentionsView impact
Multi-body simulations with contact are non-smooth systems and wrought with discontinuities which... more Multi-body simulations with contact are non-smooth systems and wrought with discontinuities which arise due to non-interpenetration and frictional constraints. Linear systems are used for applications where real-time performance is a concern, such as interactive training or video games, which gives rise to a linear complementarity problem (LCP). A common mathematical formulation [5] of the LCP for the velocity-level equations of motion is where J ∈ R m × n is the Jacobian matrix encoding the non-penetration and friction constraints, M ∈ R n × n is the generalized mass matrix, v and f ext ∈ R n are the generalized velocities and external forces of simulation bodies, respectively, λ ∈ R m are Lagrange multipliers representing the non-interpenetration normal forces and tangential frictional forces of each contact. The box constraints defined by z lo and z hi contain the lower and upper bound, respectively, of the normal and frictional impulses.
Bookmarks Related papers MentionsView impact
Non UBCUnreviewedAuthor affiliation: University of CopenhagenFacult
Bookmarks Related papers MentionsView impact
2019 International Conference on Robotics and Automation (ICRA), 2019
Bookmarks Related papers MentionsView impact
In this project I describe the status of inverse kinematics research, with the focus firmly on the... more In this project I describe the status of inverse kinematics research, with the focus firmly on the methods that solve the core problem. An overview of the different methods are presented Three common methods used in inverse kinematics computation have been chosen as subject for closer inspection. The three methods are described in some detail. An analysis is performed where the three methods are compared, and benchmarked against each other. I conclude which of the methods are the most promising and what their respective forces, weaknesses and prospects are. All figures shown are made using the test suite, developed in this project and in [4]. Source code developed for this project includes the CCD method , improvements on the BFGS method and Jacobian inverse originally developed in [4]. 1
Bookmarks Related papers MentionsView impact
Proceedings of the International Conference on Computer Graphics Theory and Applications, 2010
Bookmarks Related papers MentionsView impact
We present the RPI-MATLAB-Simulator (RPIsim) as an open source tool for research and education in... more We present the RPI-MATLAB-Simulator (RPIsim) as an open source tool for research and education in multibody dynamics. RPIsim is designed and organized to be extended. Its modular design allows users to edit or add new components without worrying about extra implementation details. RPIsim has two main goals: 1. Provide an intuitive and easily extendable platform for research and education in multibody dynamics; 2. Maintain an evolving code base of useful algorithms and analysis tools for multibody dynamics problems. Although research often focuses on a specific subset of problems, work too often begins with developing software in a broader scope simply to realize a test bed for research to begin. It is our hope that RPIsim alleviates some of this burden by decreasing development time, thusly increasing efficiency in research. Further, we aim to provide a practical teaching tool. Because it is a fully working simulator, and since it offers the instant gratification of visualized conta...
Bookmarks Related papers MentionsView impact
In this project I describe the status of inverse kinematics research, with the focus firmly on th... more In this project I describe the status of inverse kinematics research, with the focus firmly on the methods that solve the core problem. An overview of the different methods are presented Three common methods used in inverse kinematics computation have been chosen as subject for closer inspection. The three methods are described in some detail. An analysis is performed where the three methods are compared, and benchmarked against each other. I conclude which of the methods are the most promising and what their respective forces, weaknesses and prospects are. All figures shown are made using the test suite, developed in this project and in [4]. Source code developed for this project includes the CCD method , improvements on the BFGS method and Jacobian inverse originally developed in [4]. 1 Figure 2: Figure reaching for a moving ball, posed with bfgs. The figure have been constrained to obtain a more realistic pose. The source can be found at http://www.opentissue.org/svn/OpenTissue/b...
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
This paper presents our adaption of an approach to achieving a virtual reality like experience on... more This paper presents our adaption of an approach to achieving a virtual reality like experience on a typical monitor using the Nintendo © [19] Wiimote. By using the infrared camera on the Wiimote combined with infrared light emitting diodes positioned on the user’s head, we achieve the effect that the content visible on the monitor adapts to the position of the head relative to the monitor. Thereby we achieve the same effect as when looking through a window; what is visible depends on the angle and distance from the window.
Bookmarks Related papers MentionsView impact
Proceedings of the ACM on Computer Graphics and Interactive Techniques, 2021
We present a method for reconstructing the global position of motion capture where position sensi... more We present a method for reconstructing the global position of motion capture where position sensing is poor or unavailable. Capture systems, such as IMU suits, can provide excellent pose and orientation data of a capture subject, but otherwise need post processing to estimate global position. We propose a solution that trains a neural network to predict, in real-time, the height and body displacement given a short window of pose and orientation data. Our training dataset contains pre-recorded data with global positions from many different capture subjects, performing a wide variety of activities in order to broadly train a network to estimate on like and unseen activities. We compare training on two network architectures, a universal network (u-net) and a traditional convolutional neural network (CNN) - observing better error properties for the u-net in our results. We also evaluate our method for different classes of motion. We observe high quality results for motion examples with ...
Bookmarks Related papers MentionsView impact
Computational Diffusion MRI, 2021
Bookmarks Related papers MentionsView impact
ACM SIGGRAPH 2021 Courses, 2021
Bookmarks Related papers MentionsView impact
Proceedings of the ACM SIGGRAPH / Eurographics Symposium on Computer Animation, 2017
Bookmarks Related papers MentionsView impact
Proceedings of the International Conference on Computer Graphics Theory and Applications, 2010
Bookmarks Related papers MentionsView impact